. >> woodruff: dr. garryat is your understanding of the drug and its comfort level of it being given to the one or two american healthcare workers. >> i am very comfortable having the americans being given the treatment. they're both healthcare workers and knew the risks of taking the drug so they were fully informed of the possible outcomes. as americans, we need to do all we can to protect people that go to countries where very serious disease like this is occurring and do all we can to protect them if they should be unfortunate enough to get infected. so this drug, zmapp, has shown very good promise in experimental animals, these antibodies are very promising drugs, at the very top of the list for hemorrhagic fevers like ebola. >> woodruff: does that mean it would be more widely distributed at this point, dr. garry? >> when i came back from sierra leone about a month ago, i realized the outbreak had the potential unlike any other to spread wider and inif we could more people because it was in west africa i

dr. garry, thank you for joining us. >> my pleasure. >> to another growing crisis.his one in ukraine where there are heightened concerns and signs of an invasion by russian forces in the southeast. president obama warned of further action against russia after nato released satellite images. those images support the claim that russian forces are helping separatists. an emergency meeting of the u.n. security council members express the outrage over the latest escalation. there were emergency meetings in ukraine's capitol, kiev, the country's president, urging his security team to avoid a panicked response that could worsen the situation. america tonight's sheila mcviccer has the very latest? >> the satellite images are some of the evidence produced by nato of russian forces on the ground inside ukraine. they show them near the previously quiet border town novask. prompting residents to flee. >> these latest images provide concrete examples of russian activity inside ukraine. they are only the tip of the iceberg in terms of the overall scope of russian troops and weapo